Eli Schwartz

Microfluidic fluorescence immunoassays enable sensitive biomarker detection, but performance is limited by inefficient capture on planar surfaces and background fluorescence from unbound labels. Here, we present chip-based optical modulation biosensing (Chip-OMB), combining three-dimensional magnetic bead-based target capture, bead immobilization, internal fluid flushing, and modulated optical background subtraction. Magnetic beads are concentrated and immobilized in the chamber, while controlled on-chip flushing displaces unbound fluorescent labels without requiring user-performed washing after chip loading. Alternating optical interrogation of the bead cluster and surrounding solution enables background subtraction. Using fluorescently labeled magnetic beads, Chip-OMB achieved limits of detection of 0.1 pM in buffer and 22 pM in undiluted plasma, corresponding to 580-fold and 22-fold lower equivalent fluorophore-concentration limits of detection, respectively, than conventional steady-state bulk fluorescence measurements using a plate reader. Measurements correlated with the laboratory optical modulation biosensing system (R² = 0.98). In an anti-dengue virus serotype 2 (DENV-2) nonstructural protein 1 (NS1) immunoglobulin G (IgG) immunoassay, Chip-OMB achieved a 3 ng/mL limit of detection with a ~4-log dynamic range. Among 56 sera, 29 DENV-2 cases confirmed by reverse transcription quantitative polymerase chain reaction (RT-qPCR) were Panbio IgG-positive and above the exploratory Chip-OMB cutoff, while all 27 study-defined negative controls were below it.

Purpose: The clinical significance and optimal treatment of Dientamoeba fragilis (DF) infection remain controversial, despite its frequent detection in patients with chronic gastrointestinal symptoms. This study aimed to evaluate clinical and molecular responses to various antiparasitic regimens and to assess the association between symptom resolution and parasite eradication. Methods: In this prospective, single-center observational study conducted between January 2019 and June 2023, we included 105 symptomatic patients with a positive stool PCR for DF. Patients were treated with paromomycin (PAR), nitroimidazole monotherapy (NM; metronidazole/tinidazole), or a combination of tinidazole and albendazole (T + A). Clinical and molecular outcomes were assessed one month post-treatment using a structured symptom questionnaire and repeat PCR testing. Results: Of 96 patients with follow-up, 73 underwent repeat PCR testing. PAR was associated with significantly higher clinical and molecular cure rates (82.8% and 88.5%, respectively) compared to T + A (35.0% and 29.2%) and NM (4.2% and 10.0%). Combination therapy with T + A was superior to NM in clinical response but not in molecular clearance. A strong correlation was observed between clinical cure and DF eradication (p < 0.00001), reinforcing the pathogenic role of DF. Median symptom duration before referral was 9 months, indicating the chronic nature of untreated infection. Conclusions: DF should be considered in patients with unexplained chronic gastrointestinal symptoms. Molecular testing is recommended for accurate diagnosis. Paromomycin appears to be the most effective treatment, with a strong association between clinical recovery and microbiological cure. Randomized controlled trials are warranted to further define optimal management strategies for DF infection.

Dengue virus (DENV) poses a major global health concern, with over 6.5 million cases and 7300 deaths reported in 2023. Accurate serological assays are essential for tracking infection history, evaluating disease severity, and guiding vaccination strategies. However, existing assays are limited in their specificity, sensitivity, and cross-reactivity. Using optical modulation biosensing (OMB) technology and non-structural protein 1 (NS1) antigens from DENV-1–3, we developed highly sensitive and quantitative serotype-specific anti-DENV NS1 IgG serological assays. The OMB-based assays offered a wide dynamic range (~4-log), low detection limits (~400 ng/L), fast turnaround (1.5 h), and a simplified workflow. Using samples from endemic (Vietnam) and non-endemic (Israel) regions, we assessed intra-DENV and inter-Flavivirus cross-reactivity. Each assay detected DENV infection with a 100% sensitivity for the corresponding serotype and 64% to 90% for other serotypes. Cross-reactivity with Zika, Japanese encephalitis, and West Nile viruses ranged from 21% to 65%, reflecting NS1 antigen conservation. Our study provides valuable insights into the cross-reactivity of DENV NS1 antigens widely used in research and highlights the potential of OMB-based assays for quantitative and epidemiological studies. Ongoing efforts should aim to minimize cross-reactivity while maintaining sensitivity and explore integration with complementary platforms for improved diagnostic precision.

Background: Leishmaniasis, mainly cutaneous leishmaniasis (CL), is endemic in Israel. In recent years, the diagnosis of leishmaniasis has transitioned to a molecular diagnosis. Objective: To summarize all cases of leishmaniasis and the identified species seen in Israel based on molecular diagnosis. Methods: A retrospective study was performed of patients diagnosed with leishmaniasis between January 2017 and December 2022. All five medical centers in Israel in which Leishmania diagnosis is performed were included: Soroka, HaEmek, Hadassah, Rambam, and Sheba, all utilized molecular diagnostic methods. Data on the annual number of cases, species, age, and gender were retrieved. Results: During the years 2017–2022, a total of 4168 cases of leishmaniasis were diagnosed, which corresponds with ~7/100,000 inhabitants. L. (L.) major and L. (L.) tropica accounted for 84% and 14%, respectively. During the years 2020–2021, L. (L.) infantum emerged as a new form of cutaneous disease [2.7% of cases during this period]. Visceral L. (L.) infantum was found in five cases. Imported New World leishmaniasis accounted for 1% of the cases. L. (L.) major affected more males (67%) while L. (L.) tropica commonly affected more children and caused more facial lesions. Conclusions: The mean annual number of cases during these years is ~700. The dominant species is L. (L.) major. Since 2020, cutaneous L. (L.) infantum is an emerging infection in Israel.

Miltefosine, an orally administered drug, is an important component of the therapeutic arsenal against visceral and mucosal forms of leishmaniasis. However, data regarding the safety and tolerability of miltefosine treatment for cutaneous leishmaniasis (CL) are relatively limited. The aim of this study was to evaluate the tolerability, safety, and adverse events (AEs) of miltefosine treatment in patients with CL. In this cohort study, we reviewed the medical records of all miltefosine-treated patients between 1 January 2016 and 31 December 2022, at Israel Defense Forces military dermatology clinics and the dermatology and Tropical Medicine Clinics at Chaim Sheba Medical Center, Ramat-Gan, Israel. A total of 68 patients (54 males, 79%) with a median age of 30.3 ± 15.6 years (range: 18–88) were included in this study. Leishmania species were identified as L. major (n = 37, 54.4%), L. tropica (n = 12, 17.6%), L. braziliensis (n = 18, 26.5%), and L. infantum (n = 1, 1.5%) using polymerase chain reaction (PCR). Miltefosine tablets were administered orally at a dose of 50 mg, three times daily, for 28 days. Overall, 44 patients (65%) completed the 28-day treatment, and the remaining patients required dose reduction or early discontinuation of treatment. AEs (of any degree) were common, reported in 91% of patients. Both previously reported and previously unreported AEs were documented. Gastrointestinal symptoms (66.1%) and malaise (23.5%) typically occurred during the first two weeks of treatment and tended to subside. Other AEs, including acute renal failure (20.6%), sudden and severe pleuritic chest pain (7.6%), acne exacerbation (11.8%), suppuration of CL lesions (17.8%), and AEs related to the male genitourinary system (39.6% of males), typically occurred towards the end of treatment. The latter included testicular pain, epididymitis, diminution or complete absence of ejaculate, inability to orgasm, and impotence. Severe AEs necessitated treatment discontinuation (29.4%) or hospitalization (10.3%). URTI-like symptoms, arthritis, cutaneous eruption, pruritus, and laboratory abnormalities were also observed. Overall, the cure rate (for all patients combined) evaluated 3 months after the completion of treatment was 60%. The tolerability of miltefosine treatment for CL is low. Close clinical and laboratory monitoring is required during treatment, as severe AEs are not uncommon. As new insights regarding its toxicities emerge, further studies are required to define the role of miltefosine in the treatment of CL.

Phylogenetic analysis of dengue serotypes 1 and 3, which were diagnosed in travelers and Nepalese infected in Kathmandu during the October 2022 outbreak, revealed that both serotypes were clustered closest to the sequences sampled in India. This suggests both serotypes may have originated in India.

Background: Dengue fever (DF), caused by the dengue virus (DENV), is the most common arboviral disease in travellers worldwide. It is hypothesized that compared with primary DF, secondary DF may result in antibody-dependent enhancement of the immune response, resulting in more severe disease. We aimed to compare clinical and laboratory parameters in travellers with primary and secondary DF to determine whether secondary DF is associated with markers of severe disease. Methods: We conducted a retrospective cohort study, which included all patients diagnosed with DF at the Central Virology Laboratory of the Israeli Ministry of Health during 2008–19. Clinical, laboratory and virological data were extracted from laboratory and patient records. A diagnosis of DENV infection was based on a positive nonstructural protein 1 (NS1) test, polymerase chain reaction or serology testing for immunoglobulin M (IgM) and immunoglobulin G (IgG). Primary and secondary infections were classified based on travel history, NS1 result and IgM/IgG ratio. Severe DF was defined according to WHO classification. Results: We identified 245 DF cases: 210 (86%) primary and 35 (14%) secondary. Whilst fever duration was significantly longer in secondary compared with primary infections (6.4 vs 5.3 days, P = 0.027), mean Aspartate aminotransferase levels were significantly higher in primary compared with secondary cases (146 vs 65 U/L, P < 0.001), and no other clinical or laboratory parameter differed significantly between the groups. Of note, only four patients had severe DF, all had primary infections and none died. Conclusions: In a cohort of returning travellers with DF, secondary infection, compared with primary infection, was not associated with a consistent trend towards greater severity of the clinical and laboratory markers examined in this study.

An unusual case of leishmania braziliensis in a traveler with persistence of prominent lymphadenopathy for three years despite appropriate treatment and complete resolution of the primary lesion. The case is accompanied by an ultrasonographic description of leishmania.